So you must have some loader installed that is replacing the Gigabyte SLIC with the HP SLIC 2.1 and not letting the BIOS Mod do it's job.
Uninstall ANY Loader and then look at it again with SLIC Dump Toolkit.

That just means you must have used a modded BIOS that had HP SLIC added and NOT Gigabyte or a Loader is On that system.
The one I linked has Gigabyte NOT HP.
So, Obviously you didn't flash the one linked above or you have some loader installed.

If you want Gigabyte SLIC just Flash the Bios Mod linked above from DOS with FlsahSPI and see what happens.